1. Field of Invention
This invention relates to apparatus and method for mooring of marine structures. With more particularity, this invention relates to methods and apparatus for installation and use of gravity installed anchors, that is, those which embed in a seabed by virtue of being dropped from a height above the seabed and being allowed to fall to the seabed of its own weight.
2. Description of Prior Art
Gravity installed anchors that are installed by freefalling under the force of gravity are known in the art. These anchors are lowered down through the water column to a desired height above the seabed, and then released, whereby their own weight carries the anchor to and into the seabed under the influence of gravity. Examples of existing known examples of gravity installed anchors of this type include U.S. Pat. No. 6,106,199 to Medeiro, Jr. et al (Aug. 22, 2000) and U.S. Pat. No. 6,257,166 to Lieng (Jul. 10, 2001). Prior art methods of installation of these types of anchors are disclosed in those two patents as well. Such methods include a free fall of the anchor, wherein it is simply lowered to a desired height above a seabed then released, with or without a speed limiting device (e.g. a drogue) attached to the anchor; or a procedure wherein the anchor remains connected with the launch vessel via a cable, etc., and the cable is unspooled from the winch, etc. on the launch vessel fast enough that sufficient speed can be developed by the anchor as it falls.